题型:填空题 设椭圆C:x2a2+y2b2=1(a>b>0)的离心率e=12,右焦点到直线xa+yb=1的距离d=217,O为坐标原点.(Ⅰ)求椭圆C的方程;(Ⅱ)过点O作两条互相垂直的射线,与椭圆C分别交于A,B两点,证明点O到直线AB的距离为定值.并求出定值. 查看答案
题型:填空题 Ram explained to his mother _____ he would get home late that night because of extra work.A.thatB.whichC.whatD.whether 查看答案